Electric heating device.



G. P. MADSEN.

ELECTRIC HEATING DEVIGE.

APPLICATION FILED FEB.11, 1911.

1,034,2 5, Patented July 30, 1912.

' 1 2 SHEETS-SHEET 1.

Witnesses G. P. MADSBN.

ELECTRIC HEATING DEVIGE.

APPLICATION FILED IEB.11, 1911.

1,034,265. l atented July 30, 1912'.

2 SHEETSSHEET 2.

Witnesses T i j j if; -1 Inventor wdmz gw.

C12 2"263 PMadsen heaters for sad ironsand the like.

pthersskilled in the art to which it appertains to make and use the same. 1

-' an electric heater wherein the heating pormay be made as a separate and distinct ar- 3 be heated.

heating-member comprising a pro-formed uNi E-D STATES PATENT form-cu.

CI-IARLES P. MADSEN, OF "CHICAGO, ILLINOIS, ASSIGNOR, BY ME SNE' ASSIGNMENTS,

TO-PELOUZE MANUFACTURING COMPANY, OF CHICAGO, ILLINQIS, A CQRPQBATIQN OF ILLINOIS.

ELECTRIC HEATING DEVICE.

V Patented July 30,- 1912.

Original application filed January 22, 1908, Serial No. 412,176. Divided and this application filed February 11, 1911. Serial No. 608,003.

To all whom it may concern: 7 p

Be it known that I, GHARLus P. MADSEN,i a citizen of the United States, and resident? of Chicago, Cook county, Illinois, have in-% ments in .an Electric Heating Device, 05; which the following is a full, true,-clear, and exact description, such as will enablei My invention relates to electrical heatingi devices and more particularly to electricali The object ot-my invention is to provide? tion or elementyvill be. arranged in a single 5 plane and capable of being placed in close; proximity to the article to be heated, theref by preventing loss of" heat by dissipation; which will have a suitable mounting for the heating elementwherein the conductor is embedded and suitably insulated; and which tide. of manufacture at comparatively low cost and capable of being mounted or re moved as a unitary self-contained structurefj in the bodyot a sad iron or like article to Another and more particular object of my invention is to provide a sad iron which will have a member to be heated and a member for supplying the necessary heat thereto, which member will be a self-contained structure associated with the heated member but readily separable therefrom as a unit.

Broadly my invention consists in an elect-rical heating device comprising amount ing or supporting part and an electrical heating coil, th'e turns-of'which are separated by insulating material preferably wound up simultaneously with the conductor in a single plane, and preferably bound together by a layer of insulating cement, the Whole Wound form being bodily cemented to said mounting. v

My invention further consists of a heat-, ing element, as above stated, which may be made in the form of unit adapted for mounting in the bodyof the sad iron and vented certain new and useful Improvef for interlocking cotiperation with the other thereof can be readily disassembled or assembled by a person unskilled in such matters, and the heating'element removed or replaced without disturbing the-proper rand, .p're-arranged relations of all of the parts of the iron.

I will describe my invention by reference [to the accompanying drawings wherein:

Figure' l is aside elevation of a sad iron embodying my invention; Fig. 2 is a trans- -E verse vertical section on line 22 of Fig.

1; Fig. '3 is a vertical, longitudinal-sectional view taken through the center of the-iron shown'in Fig. 1; F ig. 4 is a view similarto Fig. 2, but taken on the. line of Fig. 3,; Fig. 5 is a perspective. view of the heating member; Figs. 6 andii'i'areperspective views of the mounting and'ffthepro-formed heating element respectively ready to be assembled; Fig. '8 is an enlarged transverse sectienal view of a portion of the heater showing the detailed construct-ion thereof; and

Fig. 9 is' a bottom plan view of a mo dified' torm of heater.

As will hereinafter appear, my invention is capable of being adapted by suitable modification to various articles to be heated,

but for the purposes of illustration I have chosen one embodiment of my invention which has been particularly designed for heating sad irons of the type described and claimed inmy co-pending application, Se-

rial No. 412,176, filed January 22nd, 1908,

wherein my present invention was originally fully disclosed.

In general the body portion of the iron comprises a top or weight element W and a bottom element or'ironing plate H, and between and separating these parts is interposed the heater member I. By this arrangement the heater serves to insulate the member W from the bottom plate H so as to reventthe heat from reaching said member and rendering, it too hot for comfortableuse. A suitable handle G is provided for manipulating the iron and is. carried by an v upstanding post or standard P securedto the front end of the iron.

The heater (Figs. 5 to inclusive) consists of a backing plate or mounting 1 and a heating conductor 2 buried or embedded in one side thereof. The mounting 1 may be of any suitable material, but I prefer to make it of insulating material which is preferably tough, refractory and substantially incompressible material suitably conformed to the desired shape by hydraulic pressure. These qualities render it capable of withstanding the blows to which it is subjected when used in a sad. iron heater and furthermore it properly insulates the two other portions of the iron between which the heater is interposed. Obviously .it may be given any suitable shape to adapt it to the article which is to be heated, but in the present structure I have shown it as substantially triangular in shape and conform-i ing to the general shape'of the sad iron.

The heating conductor 2 is preferably a resistance ribbon of suitable cross-sectional area to give the desired results, but it is obvious that a resistance wire of circular or other geometric cross-section may be used if desired. This conductor is arranged in the form of a thin, fiat coil before it is applied to its mounting. In making this heater coil I wind the heating conductor volutely in one plane although I may, if desired, wind it reflexively in a single plane, the ribbon being presented edgewise to the mounting plate. I prefer to insulate the turns of the coil by a comparatively soft, loose material, such as asbestos. This I prefer as an insulating substance for the reason that it efi'ectually withstands the heat and it permits the resistance ribbon to expand or contract with the variations in temperature. It is possible to interpose loose asbestos between the turns after the coil is wound, but because of the impracticability of this method I use a ribbon or strip 2 of asbestos about as wide as the resistance ribbon and somewhat thicker and to wind it up in parallel. with the resistance ribbon. I prefer, however, to use an asbestos string, thread or yarn which can-be bought standard on the market and which assumes the form of a ribbon due to the pressure in windin The process of maklng the heater form may be accomplishedby winding the ribbon and asbestos strip together in'a single plane between, two plates. Incidentally the coil :may be given a substantially triangular ordinary factory methods of manufacture the form would naturally be subjected to some handling before it is mounted on the backing member. F or this reason I prefer "to bind the turns together more substantially. I may, if desired, trail the asbestos through abath of liquid cement or adhesive prior to winding it in thecoil, but I find that the best method with a 'ribbon conductor is to apply a binding layer of insulating cement 3 on one face or side of the form, this being generally done as soon as the coil is removed from the winding machine. By applying a thin layer of cement in this manner the turns of the winding are firmly secured and the whole wound form rendered comparatively stiff and unitary so that it will withstand considerable handling before it is firmly mounted. Especial care need not be taken, as shown in Fig; 7, to apply this first layer of cement with any degree of uniformity for the reason that it serves principally as a binder unless a metal backing plate is used. In this case the cement had better be applied smoothly and evenly so as to properly insulate the conductor from the'plate. The cement which I find to be the most satisfactory for this purpose, is of the self-hardening kind, that is, cement which'is made of a pasty consistency and which solidifies or hardens on drying.

l/Vhile it is possible to provide the insulating plate 1 with a smooth, flat surface and attach the formed heater coil by additional cement, I find by experiment thata more satisfactory structure is obtained by making a broad, shallow, fiat-bottomed recess I in one side of the plate and placing the heat-er form flat against the bottom of this recess, and burying or embedding the form therein bymeans of more cement as indicated by 3. Thisadditional quantity of Ce ment fills in around the edges of the heater form and also fills other interstices so that the face of the heater element presents a generally smooth appearance.

Fig. 7 shows a pre-formed heater coil with the binder layer of cement roughly applied, portions of the winding being exposed to the atmosphere. This form is ready to be embedded in the plate 1 with its cemented side against the bottom of the recess I".

My purpose in winding the ribbon in triangular 'form with an open center 3 is to distribute the heat more around the edges and point of the iron since the points come in contact with the damp cloth first, the center of the ironing surface being left comparatively cooler so as not to scorch the cloth. Fig. 9 shows the heater coil wound in To complete the heater unit, the inner and outer ends. of the ribbon are connected to upv standing contact blades 6 whichconstitute terminals for the winding (Figs. 3, 4 and 5). I The blades are held in parallel relation by means of an insulating block or column 7 which is fitted and secured into a rectangular opening 8 in the insulating plate I. The contact plates project upwardly beyond the upper end of the post 7 and into a channel or recess 9 in the upper side of the member W so that they are in position to cooperate with a movable switch plug for connecting the heater to the source of current.

The ironing plate or bottom element of the iron comprises a flat, thin, rimless metal plate H, substantially triangular in shape, and having a polished bottom surface for ironing purposes... This plate has an up-' standing enlargement H centrally located,

and preferably of triangular shape so as to i interlock with the correspondingly shapedrecess or socket I" in the heating member,

the object of this arrangement being toprevent relative rotation of the heating member. and the .plate. The under face 'of' the heater unit, wherein is embedded the heat- 1 ing coil, lies flat against the upper face H of the bottom plate so that the heat is trans j mitted directly to the plate without any loss.

In order to provide against any possibility; of the exposed edges 'of the heating conductor 2 coming in contact with the metal of; the ironing plate, I prefer to interpose a? thin sheet of mica M. i

As previously stated, the'heater element constitutes an intermediate member lot the'i body of the iron and is interposed between the weight member W and the bottom member or plate H. It is particularly desirable that the upp'erportion of! the body of the. iron and the handle be maintained as coolas possible and for that reason I have pro- 5 vided the member W with a large. cavity 10 which fits over and is preferably completely f filled by the upper portion of the heating member, as clearly shown'in Figs. 2, 3 and i 4:. This provides a comparatively thick I body of insulating material between the? edge I of -the heater so as to provide a5 peripheralinterlook between said parts. It?

. will thus be seen that when the ironing? plate, the heater member and the weight;

member are assembled together they are all 3 interlocked with each other and-there is no possibility of displacement or' relative rotation. In order to clamp these parts in their 5 proper relation, I provide the ironing plate with a central upstanding bolt or 'post 12 whichpasses upwardlythrough holes in the i heating member and the weight member W, i

and upon its upper end threaded to receive the wing clamping nut 13. The hole 14 in the member W through which the bolt passes is enlarged to preventmechanical contact and eliminate the possibility of the member W' absorbing heat from the post. The insulation of the upper member is further perfected by means of an insulating washer 15'clamped under the nut 13. The wing nut, washer and the upper end of the bolt all lie within a deep depression or re cess 16 in the upper member.

As before stated, .the contact blades 6 of the heater element project upwardly beyond the upper end of the insulating post 7 and into the rectangular groove or recess 9. This channel or recess 9 extends to the rear end of the iron and constitutes a guide for the movable switch plug R. This switch plug is preferably reciprocatory or movable.

in the guide channel so that it may be moved to engage or disengage the contact blades. I have positioned this switch on'the'iron beneaththe handle .G in such manner that it may be moved by the hand gripping the hanironing. In addition to this I have arranged this plug so that it may be entirely removed from the iron when -it is desired to 'completely disconnect the'same from the circuit, 1 The small knob 18 carried by the switch forms a convenient im-eans by which 1 the switch is operated. The switch is yieldingly maintained in its guide channel by means of asprin'g member 19, one end of which is clamped under the insulating washer 15 which holds it securely in place. The other end of the spring lies above. the switch plug and substantially parallel thereto. This end of the spring is bifurcated and the free ends of the bifurcations are bent to form latches which snapinto the grooves 20 in the upper face of the switch block. These grooves correspond to 'the different positions of the switch in its channel; thus this spring yieldingly presses uponthe switch and 'holdsit in either of its positions, but does not interfere with the complete removal of the switch block from the iron to completely disconnect the same. The switch plug itself may be of any suitable construction, but I find the form shown particularly in Figs. 3 and 4 to be best adapted to the sad iron shown in the drawings, The switch comprises a small rectangular, block having two parallel longi-v 'tudinal bores 21 and slots 22-communicating openings or recesses to permit the contact blades 6 of the heater elementto-e'n'ter the "switch block and-engage the terminals 23 which are positioned in respective longitudinal bores of the plug; The conductors which convey the current to the iron are secured to these terminals. and pass upward through holes in the block and make a double turn underneath an upstanding projection or and is claimed in my copending application Serial No. 608,051 and is not specifically claimed herein. The said application 608,051 and this present application are both divisional applications of my copending applicatiorf Serial No. 412,17 6.

I claim:

1. An electrical heating device comprisinga body of insulating material having a rim upstanding from one face to form a shallow depression for receiving a heating member, in combination with a heating member substantially as thick as the height of said rim and comprising a flatly wound ribbon conductor, a binder layer of insulat ing cement applied upon one face of said heating member, said member being adapted to be laid in said depression with its cemented face against the bottom of said de-- pression and its outer face. in the plane of the outer edge of the rim, a quantity of insulating cement fillingthe spaces between said rim and said heating member and firmly securing said heating member in said depression, and a thin flat sheet of insulating material laid .flat upon and in contact with both the outer edges of the rim and the free surface 'of the heating member.

2. An electrical heating device comprising a body of insulating material having an outer and an inner rim of even height upstanding from one face to form a shallow depression or trough for receiving a heatmg member, in* combination with a fiat heating member substantially as thick as the height of said rims and comprising a suitably insulated, flatly wound conductor, a layer of insulating cement applied upon one face of saidheatmg member said member being laid bodily in said groove with its cemented face against the bottom thereon, a quantity of insulating cement filling the spaces etween said rims'and said heating member and firmly securing said heating member in said depression, and an upstanding terminal on the opposite side of said -mountingconnected to said heating member. I

3. In an electric heater for sad irons a mounting of insulatingmaterial conformed to the shape of the iron, and having a broad,

shallow recess in one side also conformed to the shape of the iron, a preformed heating element conformed to the shape of the recess and comprising a ribbon resistance and a strip of insulating material compactly wound together in one plane, and permanently consolidated by a layer of cement applied to one face thereof, said heating elev comparatively thin, flat plate of hard rei,

fractory insulating material of substantially triangular shape and having a central opening, an inner and an outer upstanding rim forming therebetween a broad, shallow recess of substantially uniform depth throughout for receiving a heating element, in combination with a pre-formed heating coil comprising a ribbon resistance and a strip of asbestos wound together in a single plane, insulating material securing the turns of said heating coil together, said coil being substantially as thick as the depth of said recess and conformed to fit therein, and a quantity of adhesive insulating material firmly securing said coil in place in said recess. 1 i

5. As an article of manufacture an electric heating element comprising a substantially triangular pre-formed, self-sustaining heating element arranged in a thin, flat plate, a correspondingly shaped flat plate of hard refractory insulating material having a recess in one face for receiving said preformed heating element, and a quantity of insulating cement holding said heating element securely within said recess and substantially flush with the edges thereof.

heater unit adapted for mounting in the body of a sad iron, comprising a flat, triangular plate of refractory; insulating material having a central portion for interlockment with the portion of the iron to be heated, a comparatively broad recess in the 'face of said plate, a pre-formed heating coil comprising a ribbon resistance and a strip of asbestos wound together in a thin, flat plane, a layer of cement binding the turns of said coil together, said coil being laid in 'said recess in substantially mechanical contion with an electric heater comprising a In testimony whereof, I have hereunto set ribbon resistance and a strip of insulating I my hand, this lth'day of February, 1911, in material compactly wound volutely upon the presence of two subscribing Witnesses. itself in a single plane, a layer of adhesive CHARLES P. MADSEN. material binding the turns together, and a separate quantity of cement embedding and firmly attaching said heater in said recess.

Witnesses:

JOHN R, LEFEVRE, LUTHER JOHNS. 

